Coating devices for coating metal bands are used, for example, for galvanizing metal bands and sheets. To accomplish this, the metal band is drawn through a zinc melt of about 450° C. The metal band continuously dives downward into the zinc melt, is deflected upward by a rotating shaft in the melt and runs upward out from the zinc melt. In the melt, the shaft is supported in open sliding bearings that are subjected to high wear due to the great forces prevailing, the high temperatures of the zinc melt and the great chemical aggressiveness of the zinc melt. In a ceaselessly operating coating installation, it takes only a few days until the sliding bearings are worn out to such an extent that they have to be replaced. Replacing the two bearings of a guide roller takes several hours which represents an important cost factor with coating installations worth between 100 and 200 million DM.